The specific way for law firms to negotiate fees depends on many factors, including the overdue amount, the complexity of the case and the required workload. Generally speaking, law firms will adopt the following charging methods:

1. Fixed fee: A law firm can charge a service fee according to a certain fixed amount, regardless of the success or failure of the case.

2. Proportional fees: Law firms can charge service fees according to a certain proportion of overdue amount, usually between 5% and 20%. This means that the higher the overdue amount, the corresponding service fee will increase accordingly.

3. Result fee: Some law firms may adopt the method of result fee, that is, they only charge fees after successful negotiation to solve overdue problems, usually a certain proportion of overdue amount, such as 10% to 30%.

To sum up, the charging methods negotiated with legal companies after online loans are overdue usually include fixed fees, proportional fees and result fees. The specific method depends on the overdue amount, the complexity of the case and the required workload.

Extended data:

Law firms usually provide professional legal advice and negotiation skills to help borrowers and creditors reach an ideal solution when negotiating overdue online loans. In addition, law firms can also draft relevant agreements, provide legal advice and defend in court on behalf of borrowers.

This answer is based on common sense and general situation. If there are special circumstances or specific legal provisions apply, please consult a professional legal institution for detailed consultation. )